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NOAA/ PMEL/ OERD

Geodetic Calculations

By T-K Andy Lau 		Requirement
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References

Parameters for Both Geodesic and Geodetic Position Calculations

Equatorial Radius: Polar Radius: Both Radii and Distance are in
Inputs for Latitudes, Longitudes and Azimuths are all in decimal degrees.

Geodesic (shortest distance) Calculation

From Lat: and Lng: to Lat: and Lng:

Distance: between the 2 points above and the

Foreward Azimuth: Backward Azimuth: in degrees (to deg.min.sec).

for comparsion checking.

Geodetic Position Calculation

From Lat: and Lng: F.Az: , and Distance:

Lat: , Lng: and Backward Azimuth: in degrees (to deg.min.sec.).

for comparsion checking.

Convert Degree: Minute: Second: to or from Decimal Degrees:

Reference

"Spheroidal Geodesics, Reference Systems & Local Geometry" by Paul. D. Thomas U.S. Naval Oceanogaphic Office. SP-138.

A copy could be obtained from the U.S. Goverment Printing Office : 1970 -- 372-397 if it is still in prints.

Note there is not special reason why the Thomas's meothod was chosen to be implemented. It was the first method that was encounted. It turns out it is one of many non-iterative algorithms for computing the solutions of geodesics.